About a year ago I spent about $800 replacing everything on the a/c system. Compressor, evaporator, condensor, drier, blower motor, orfice tube, accumalator and added dual 12" Be Cool fans. The a/c blew in the upper 30's until about 2 weeks ago and now it wont blow below 68. I've checked the freon and it not low. Nothing blocking the condensor. Is there a way to tell if the compressor is going out or bad without spending $300 to replace? I live in South houston and it's pretty hot here right now. I'm not sure if something could be clogged. When I switched over, I pulled a vaccum for about 30 to 45 minutes and added the new oil to the compressor. Ever since I've had the car, the previous owner jumped something to where the clutch stays engaged with the a/c on. It doesn't cycle. Could this cause premature compressor failure?? The compressor does make a knocking noise with the a/c on. I'm not sure if I should try to switch to Auto Frost. What would I have to do or replace if I went that route. It just sucks spending $800 bucks a year ago, I don't want to spend that kind of money again! Sorry so long, just tring to mention everything. It was 100 degrees here today and is only getting hotter!!

 

Compressor staying on could be for several reasons.

1) Could be a variable displacement compressor instead of a cycling compressor. The variable displacement ones are supposed to be easier as they're not going on/off/on/off. They're simply a variable output type. The old GM R4 compressors are cycling. The GM V5 compressors are variable displacement.

2) Houston set an all time record high for June today (104°). Very unlikely that a cycling compressor would be cycling off in this heat even with a perfectly charged and functioning system.

Are you R-12 or R-134a?

Are both your radiator fans working properly? If they're not, the A/C performance will be dreadful.

 

Quote:

Originally Posted by mikeirocz1

.........I've checked the freon and it not low.........

 

The system was coverted to r134. I replaced the old compressor with a GM compressor. The GM compressor has a sticker that say r12 buts it's been converted. I'm not sure what model compressor it is. I called the dealer and the have a compressor kit for $446.60, R4 compressor for $382.43 or a A6 compressor for $611.17. Don't want to buy a compressor if mines not bad. I'm not sure if it's just so hot here it's not cooling as good. It started not cooling as good over the past 2-3 weeks as the temp went up. I put some leak dye in the system and couldn't find a leak. Should I convert back to R12 or autofrost?? I here those work better in high heat/humidity area's like here.

 

what are your pressures?

 

I checked the low pressure on the low side with a guage from the auto parts store and it was 65. I don't have a way to check the high side.

 

Hard to say exactly how loud the compressor should be.

Assuming your cooling fans are turning on when the A/C is on, the compressor wouldn't shut off if it's running 65 psi. The compressors tend to turn ON at about 45 psi and turn OFF at around 25 psi.

65 psi isn't cold enough to give you cold air. Needs to be down in the low 30's for that to happen.

Could very well be the compressor going out. If it's not compressing down to the low levels, it would be a sign. R-12 to R-134a changes often don't last more than a year in hot climates. It's pretty much impossible to get all the old R-12 chlorine out of the system no matter how much you flush it. And you use it more often than somebody up north would. They might be able to get 2-4 years out of a conversion.

 

65psi low side could mean a few things, first thing to check is your fans are turning on. if they are then it could mean you are either over charged or you compressor is failing. i've seen r12-r134a conversions last for numerous years, and i've seen them only last for a month, its kind of hit or miss with the conversion. but if you are trying to troubleshoot an a/c system, you really need to be able to read both high and low side pressures.

 

When I coverted the system, I replaced all the components so there shouldn't be any R12. My friend has some guages I can hook up to the high and low side. What should the high and low side read with a/c on and clutch engaged and what should it read off? My fans are both running, I have the dual 12" puller becool fans.

 

low and high side pressures should read the outside temperature while the a/c system is off

with the a/c system running the low side should be approximately 30-50 psi depending on the outside temperature, hotter the outside temp, higher the pressure. high side should read 225 or higher also depending on the outside temp, hotter the outside temp, higher the pressure.

these pressures are approximates only, humidity plays a factor also.

 

one thing i have see happen before, is the orifice tube break apart.. just a thought :P

 

clogging or debris in orifice tube